In a circle of radius 21 cm, an arc subtends an angle of 60° at the centre. Find the length of the arc.
Given:
Radius of circle = 21 cm
Angle subtended by the arc = 60°
∵ Length of arc = 
× 2πr
= 
× 2 × 
× 21 = 22 cm
Hence, the length of the arc is 22 cm.
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